Surgical suture adapted for enhanced visibility

ABSTRACT

A surgical suture having enhanced visual characteristics is provided. The suture has a suture filament operatively coupled to a suture needle. The suture filament includes a useful segment and a terminal segment. The terminal segment is located at a first end of the filament. The useful segment extends substantially from the terminal segment to a second end of the filament. The terminal segment is of a length of the filament that is left-over after a substantially last formable suture knot is formed using the useful segment. After the last formable suture knot is formed, the terminal segment is removed from the useful segment along with the suture needle for disposal. In order to enable visual location of the terminal segment after the same has been separated from the useful segment, the filament is treated such that that the terminal segment has distinctive contrasting light frequency characteristics.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/337,758 filed on Oct. 28, 2016 which in turn claims the benefit ofU.S. Provisional Application No. 62/247,332, filed on Oct. 28, 2015,both entitled: “Surgical Suture Adapted for Enhanced Visibility”, theentireties of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a surgical suture with enhanced visualcharacteristics to increase its visibility in cluttered or low contrastenvironments.

BACKGROUND OF THE INVENTION

It is not uncommon in the operating room for surgical sutures to belost. As used herein, reference to a surgical suture, or “suture”,includes a needle and an attached fixed length of filament. The needleis used by a surgeon to penetrate a patient's tissue and the filament isused to draw tissue together and fasten it by means of a knot. Theproblem arises for example when the surgeon has made a sufficient numberof stiches using a particular suture so as to have used up the usefullength of the suture filament, leaving only the needle and a shortlength of remaining filament which is too short to be useful. Once thesuture is thus ready to be discarded, as conventionally such sutures areone-time-use, the surgeon will place the suture where it may beretrieved and disposed of by a nurse, thereby freeing up the surgeon tocontinue with a fresh suture. When the sutures are inadvertently lostduring surgery, it is possible that the suture has been left within thepatient, but more commonly the lost suture has fallen on to the sterilefield, drapes, clothing or floor. It is often difficult in these lattercircumstances to locate the suture. Of course it is a matter ofpotentially grave concern if a suture cannot be found, as it may liewithin the patient.

Despite preventative protocols, the problem of lost surgical articlesremains an issue. A survey published by the Risk Management Foundationfor the Harvard Medical Institutions (for all malpractice claims filedagainst Harvard-affiliated institutions) revealed that the third mostcommon allegation was “retained foreign body”.

In applicant's experience, surgeons and surgical nurses commonly adoptthe procedure of counting, after each surgery, the entire contents ofneedles, sutures and other instruments in the supply table. Therefore,lost items must be located, so that the same numbers of items counted inare counted out. Retrieving lost sutures requires time and involvesvisual searching and may include various types of magnetic or fabricmops to run across the floor in an effort to pick up the lost suture.

It is known in the prior art to color a needle or suture along theentire length of the filament.

For example, in the prior art applicant is aware of a product marketedunder the name Glo-Stitch™. It is described as a monofilamentpolypropylene non-absorbable, sterile surgical suture, composed of astrand of polypropylene which has been dyed fluorescent green along theentire length of the strand.

Published Patent Cooperation Treaty patent application WO1994/002071,entitled “Fluorescent Synthetic Sutures” also discloses a surgicalsuture of improved visibility comprising a sterile, synthetic filamenthaving incorporated therein an effective amount of a colouredfluorescent dye. The synthetic filament is described as exhibiting adistinctive colour under visible light and that it is adapted tofluoresce a bright colour during exposure to ultraviolet (UV) radiation.It is taught to soak the entire suture in bright coloured fluorescentdye. The suture is taught for use in animals primarily.

U.S. Pat. No. 3,949,755 to Vauguois entitled “Surgical Ligature”describes a surgical ligature comprising a braid of filaments on whichthere is a succession of areas of contrasting shades, wherein at leastone of the shades appears dark through a film of blood and at least oneof the shades appears light through a film of blood or against an organbeing stitched. It is taught that the individual filaments can be dyedin a full bath and the filaments extruded from synthetic materials, forexample, polyester or polyamide, or regenerated materials, for example,collagen.

Conventional sutures are commercially available in standardized sizes,typically expressed in terms of the diameter of the suture or in termsof a corresponding coded size regime. Thus for example for micro-surgerya size 10/0 suture having a corresponding diameter of 0.05 mm may beemployed, and for non-micro-surgery for example a size 0 suture having acorresponding diameter of 0.4 mm may be employed. However, thestandardized size coding or suture diameter does not inform of thelength of the suture filament other than generally a micro-surgerysuture will have a shorter filament than a non-micro-surgery filament.Thus for example in applicant's experience a size 10/0 suture may have afilament which is approximately five inches long, and size 0 or 2sutures may have filaments which are typically 24-36 inches long. Astandardized suture size chart is provided as illustrative Table 1.

SUMMARY OF THE INVENTION

In a first embodiment of an apparatus according to the presentinvention, the suture filament may be described as having first andsecond opposite ends and a length therebetween. The first end of thefilament is mounted or mountable into a secured and operative engagementwith the base end of a suture needle. The base end is opposite from thesharp, distal or free end of the needle. The length of the filament mayusefully be described as having a useful segment and a terminal segment.The terminal segment is located at the first end of the filament; thatis, adjacent the base end of the needle. The terminal segment extendsalong the filament by a short distance; for example, not exceeding sixinches or so. The useful segment of the filament extends substantiallyfrom the terminal segment to the opposite second or free end of thefilament. The terminal segment may be described as the length of thesuture filament that is leftover after a last suture knot is formed ortied so as to use-up the useful length of the filament within thepatient.

The terminal segment and needle are then removed, conventionally bycutting the filament so as to sever the terminal segment from the usefulsegment. The terminal segment and suture needle are then disposed of.Only the terminal segment of the filament is adapted for enhancedvisibility so as to be fluorescently responsive with a bright colourupon exposure to ultraviolet light or otherwise treated to be highlycontrastingly visible.

According to a further aspect of the invention, the apparatus is used ina corresponding method. The method comprises forming at least onesurgical knot in a body using the useful segment of the suture filamentand the surgical needle operatively coupled to the suture filament. Themethod further comprises severing from the useful segment the terminalsegment along with the surgical needle after the useful segment has beenexpended. The method finally comprises visually detecting the terminalsegment and the suture needle based on the distinctive contrasting lightfrequency characteristics of the terminal segment.

In detail, the suture filament comprises a first end mounted to a baseend of the suture needle. Again, the suture filament presents a usefulsegment and an adjacent terminal segment between the useful segment andbase end of the needle. During a surgical procedure, after asubstantially last formable suture knot or stitch is formed using theuseful segment, the terminal segment and the suture needle are thenremoved by severing the terminal segment from the useful segment. Theneedle and terminal segment of the suture filament are then disposed ofand are easily detected based on the distinctive contrasting lightfrequency characteristics of the terminal segment.

In another embodiment, a method of manufacturing a suture filamenthaving enhanced visual characteristics is provided. The method comprisesextruding at least one bioabsorbable or nonbioabsorbable polymer toprovide a suture filament of a predetermined length. The suture filamentdefines a useful segment and a terminal segment. The terminal segment isdisposed at about a first end of the suture filament and the usefulsegment extends substantially from the terminal segment to a second endof the suture filament. The method further comprises treating theterminal segment such that it has distinctive contrasting lightfrequency characteristics. The distinctive contrasting light frequencycharacteristics enable easy visual location of the terminal segmentafter use of the suture filament.

BRIEF DESCRIPTION OF THE DRAWINGS

Table 1 lists a range of gauge sizes of sutures and correspondingdiameters.

FIG. 1, in partially cut-away plan view, is one embodiment of a surgicalsuture described herein prior to its use as also described herein.

DEFINITIONS

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs.

As used herein, the terms:

“Fluorescent” refers any material that imparts colour under visiblelight and which emits highly visible colour in pre-determined wavelengthranges when excited by ultraviolet radiation (UV).

“Suture” refers to a surgical needle and its attached filament used tostitch together tissues, for example tissues of a living body.

“Specular” refers to its common meaning, e.g., of, relating to, orhaving the qualities of a mirror, and may be any reflective surfacewhich reflects a light source.

“Light sources” may include light emitting diodes (LEDs), coherent lightsources or lasers, ultra-violet UV light sources, or other lightemitters.

“Brightly coloured” means any vivid colour so as to enhance visibilityby providing an eye-catching contrast, in this case so as to visuallymore easily see, by reason of the contrast, a needle or suture against abackground colour of the floor, upon the drapes around the sterilefield, within the patient or upon the clothing of the surgeon andattending nurses, and any of these which may also include the colour ofblood that may be on them

“Terminal Segment” means the length of the suture filament that isleftover after a last suture knot is formed or tied so as to use-up theuseful length of the filament.

“Useful Segment” means the free end of the suture filament adjacent theterminal segment.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In order to solve the problems described above, the present inventionprovides a surgical suture including a surgical suture filament havingenhanced visual characteristics to enhance the visibility of a terminalend or segment of the filament.

FIG. 1 is a representation of one embodiment of a surgical suture 100prior to its use in sewing together body tissues (not shown). The suture100 includes a filament 12 which is in operative engagement with asuture needle 10. The suture filament 12 has first and second opposedends, 12 a and 12 b, respectively and a length extending between theopposed ends 12 a and 12 b. In one embodiment, first end 12 a of thefilament 12 is secured to a base end 10 a of the needle 10. Second end12 b of the filament is a free end distal from the first end 12 a.

Suture filament 12 has a useful segment 13 a and a terminal segment 13b. Terminal segment 13 b is at the first end 12 a of the filament 12.The useful segment 13 a extends substantially from terminal segment 13 bto the second end 12 b of the filament 12. In applicant's experience, aremaining small length of suture filament 12 is retained attached toneedle 10 once the last stitch is knotted during use of a particularsuture. This is because the filament 12 becomes too short and thusstitches can no longer be easily tied with the remaining length offilament 12. This remaining length is referred to herein as the terminalsegment 13 b of filament 12.

The terminal segment 13 b may be separated or detached, for example bycutting, from the useful segment along with the needle to be disposed ofafter the last formable suture knot is formed. As stated above, theterminal segment 13 b is the left-over segment after a substantiallylast formable suture knot is formed using the useful segment 13 a.

In one embodiment, in order to easily visually locate the terminalsegment 13 b after it has been severed from the useful segment 13 a, thefilament 12 is treated such that the terminal segment 13 b hasdistinctive contrasting light frequency characteristics relative to theuseful segment 13 a.

In one embodiment, treatment of the terminal segment 13 b includesimpregnating the terminal segment 13 b with a brightly colored dyeand/or fluorescent dye. The fluorescent dye fluoresces a bright colorwhen exposed to an ultraviolet (UV) light source. Therefore, a lostsuture; that is, a suture that is disposed of and which contains theneedle and the terminal segment, is located more easily because of thecolor contrast of the brightly colored terminal segment 13 b against thedull color of standard drapes or flooring (including bodily fluidsthereon) when the terminal segment 13 b is exposed to UV light.

In order to enable easy location, it may not be necessary to impregnatethe terminal segment 13 b with a fluorescent dye. A brightly contrastingcolor in the terminal segment 13 b may enable the terminal segment 13 bto sufficiently standout so that use of UV light is not needed.

Distinctive contrasting light frequency characteristics may include, butnot limited to, brightly coloring the terminal segment or treating orforming the terminal segment so that it is specularly responsive to anapplied light source. An appropriate light source may include one ormore of: UV sources, LEDs, lasers, incandescent lights or other lightemitters as these would correspond to the desired light characteristiclisted.

In another embodiment, in addition to the terminal segment havingdistinctive contrasting light frequency characteristics, the needle 10may also have such distinctive contrast to enable ease of location of alost suture.

In one embodiment of the invention, for color, needles 10 and/or theterminal segment 13 b are colored with a bright pigment with highvisibility and contrast. In another embodiment of the invention, for usewith UV or so-called black light, needles 10 and/or the terminal segment13 b are impregnated with a fluorescent dye that imparts color whenexposed to a UV light source. In another embodiment of the invention,needles 10 and/or the terminal segment 13 b may be impregnated withmaterial that has enhanced reflective properties to produce acharacteristic glow or shine when exposed to a bright light so as to bespecularly reflective.

Colorants or coloring agents referred to herein are preferably thosethat are approved for use by the US Food and Drug Administration.

It is advantageous that only the terminal segment 13 b of the filament12 is contrastingly adapted, so as to leave the useful segment 13 a offilament 12 untreated. This is because small pieces or trimmed ends offilament 12 are, in applicant's experience, often dropped onto thedrapes and floor as being merely a by-product of cutting the filament 12after a knot is tied. These small pieces or trimmed ends advantageouslyshould not light up under UV light or have contrasting visibility, asthey are not attached to a needle and thus would distract from thesearch for a lost suture. It is thus desirable that such pieces ortrimmings of filament remain in the background or ambient conditions aslow-contrasting as they do not need to be located.

The terminal segment 13 b of the suture filament 12 is not incorporatedinto the knots retained in the patient, and the treated terminal segment13 b of the filament and needle 10 thus only passes through patienttissue as the knotting is being done, without being left present institches remaining in the patient tissue thereby reducing the risk ofirritation or inflammation of the tissue. In other words, the terminalsegment 13 b is adapted to pass through a tissue of a patient withoutleaving substantially any trace remaining in the tissue of a treatedportion of the terminal segment 13 b and/or needle 10.

In one embodiment of the invention, the suture filament 12 includes aterminal segment 13 b configured to be in the range of one to threeinches in length. In another embodiment of the invention, the suturefilament 12 includes a terminal segment 13 b configured to be preferablyin the range of three to five inches in length. In another embodiment ofthe invention, the suture filament 12 includes a terminal segment 13 bwhich is substantially ½ to ¾ inches long. Typically the larger theneedle, the longer the suture filament.

In another embodiment of the invention, using smaller needles, thesuture filament 12 includes a terminal segment 13 b which issubstantially one eighth of an inch to 2 inches long. Some sutures maybe very small and the terminal segment 13 b that is treated may only be⅛ inch to ½ inch. Applicant believes that four inches is likely aconvenient length limit with larger sutures in most instances. Thelength treated for each suture size would be adjusted to the anticipatedlength of the terminal segment and generally is 2-20% of the totallength of the filament.

Thus, without intending to be limiting to exact dimensions ordimensionally based ranges: for size 0 or 2 sutures, a useful treatedterminal segment length of the suture filament would be for example, twoinches or so, or about five percent (5%) of a 36 inch long filament; or,for a 10/0 suture the terminal segment length would be for example 5-10mm, or about four-to-eight percent (4-8%) of a five inch long filament.Thus, again without intending to be limiting, in one aspect of theinvention a treated length of the terminal segment may be expressed asbeing within the ranges of for example 3-10% of the overall filamentlength, or for example in another embodiment in the range of 4-8% of theoverall filament length, or by way of further example in an embodimentwherein the treated length of the terminal segment is substantially 5%of the overall filament length. As will be apparent to those skilled inthe art in the light of the foregoing disclosure, many alterations andmodifications are possible in the practice of this invention withoutdeparting from the spirit or scope thereof. Accordingly, the scope ofthe invention is to be construed in accordance with the substancedefined by the following claims.

TABLE 1 Size of Sutures Old Gauge (USPD) Diameter in mm 8/0 0.05 7/00.07 6/0 0.1 5/0 0.15 4/0 0.2 3/0 0.3 2/0 0.35 0 0.4 1 0.5 2 0.6 3 0.7 40.8 Ref: Suture Material & Suturing technique - Dr. Anindya Chakrabarty

What is claimed is:
 1. A suture with enhanced visibility against abackdrop into which the suture is disposed of after at least onesurgical knot in a body is formed with the suture, the suturecomprising: a needle; a length of a useful segment for forming said atleast one surgical knot; a length of a terminal segment, wherein theterminal segment is attached to a base end of the needle and is locatedbetween the base end and the useful segment; and wherein the terminalsegment remains permanently attached to the base end of the needle;distinctive contrasting light frequency characteristics on at least theterminal segment; and wherein, during use, after a last formable knot ofsaid at least one surgical knot is formed, the useful segment is severedfrom the terminal segment, and the needle with the attached terminalsegment is disposed of into the backdrop, and wherein the distinctivecontrasting light frequency characteristics on at least the terminalsegment creates a visual contrast between at least the terminal segmentand the backdrop thereby resulting in ease of location of the terminalsegment and consequently the needle to which the terminal segmentremains attached.
 2. The suture of claim 1, wherein the body is apatient receiving surgery and the backdrop includes a bloody backdrop,of an open cavity in the patient wherein said least one surgical knot isformed, a surgical gown of a surgeon forming said least one surgicalknot, a surgical field associated with the surgery, surgical drapesassociated with the surgery, or a surgical room floor associated withthe surgery.
 3. The suture of claim 1, wherein said contrasting lightfrequency characteristics are chosen from the group comprising:fluorescently responsive to ultraviolet light, brightly coloured otherthan shades of red, differently coloured relative to a colour of blood,specularly responsive to an applied light source from a tool.
 4. Thesuture of claim 3, wherein the tool is chosen from the group comprising:UV light emitter, black light emitter, LED, laser emitter.
 5. The sutureof claim 1, wherein the length of the terminal segment is shorter thanthe length of the useful segment.
 6. The suture of claim 1, wherein thelength of the terminal segment is in the range of 3-10 percent of a sumof the lengths of the useful segment and the terminal segment.
 7. Thesuture of claim 1, wherein the length of the terminal segment issubstantially in the range of 2-20 percent of a sum of the lengths ofthe useful segment and the terminal segment.
 8. The suture of claim 1,wherein said contrasting light frequency characteristics are present onthe needle.